The proposed research will utilize nuclear magnetic resonance relaxation techniques, some of which are being developed in this lab, to elucidate our understanding of the conformational flexibility of proteins and nucleic acids. Although few details are known about the conformational flexibility of biopolymers, it apparently plays an important role in many biological processes. Consequently, we will study the motions in enzymes and the influence of substrates, inhibitors, activators, and unfolding on those motions. The dynamics in nucleic acids and nucleic complexes with proteins will be investigated. Systems to be examined include DNA, tRNA, synthetic RNA and DNA, ribosomes, messenger ribonucleoproteins, and viruses. In certain cases, stable isotopes will be incorporated into the proteins or nucleic acids to provide a nucleus for monitoring the internal motions.